An ink jet recording apparatus such as an ink jet printer includes an ink jet head for ejecting ink. For example, a shear-mode type ink jet head has a piezoelectric member for pressurizing ink and ejecting the pressurized ink.
The piezoelectric member contains a pressure chamber for storing ink, and an electrode covering the inside surface of the pressure chamber, for example. When a voltage is applied to the electrode, a potential difference produced thereby causes shear-mode deformation of the piezoelectric member, and pressurizes the ink stored in the pressure chamber. The pressure chamber communicates with an opening of a nozzle, and allows ejection of the pressurized ink through the nozzle.
An ink jet head of a type having an electrode included in the pressure chamber that is subjected to direct contact with ink is known in the art. When this type of ink jet head uses water-based ink, electrolysis may develop in some cases due to a voltage supplied to the electrode. Under the condition of electrolysis, there is a possibility of formation of bubbles in the ink, or dissolution of the electrode in the ink. The use of an electrode coated with insulation film for avoiding development of electrolysis increases the manufacturing cost of the ink jet head.